The present invention is related to an improved ratchet structure of a screwdriver in which the ratchet mechanism includes a left dog and a right dog. A left and a right projecting sections of a post are cooperatively inlaid in left and right notches of the middle sections of the left and right dogs. The left and right projecting sections serve as supports for the left and right dogs, whereby the ratchet screwdriver can be more truly operated and the torque value of the ratchet screwdriver is increased.
FIGS. 6 and 7 show a conventional ratchet screwdriver. The front end of the handle 81 has a seat body 82. A stem 83 is fitted in the seat body 82. A section of the stem 83 in the seat body 82 is a toothed section 831. The seat body 82 is formed with a cavity 821 in which a ratchet mechanism 9 is disposed. The ratchet mechanism 9 has two dogs 91. The wall of the cavity 821 is formed with two dented sections 822 in which the two dogs 91 are planted. The dented sections 822 serve as supports for the dogs 91, whereby the dogs 91 can swing about the sections abutting against the dented section 822. Two springs 92 are respectively disposed between two lateral walls of the cavity 821 and the two dogs 91. The springs 92 push the dogs 91 to engage with the toothed section 831 of the stem 83. A drive block 93 is disposed between the two dogs 91. One end of the drive block 93 extends out of the seat body 82 to couple with an outer collar 84 fitted around the seat body 82. By means of turning the outer collar 84, the drive block 93 is driven and rotated to respectively push and disengage the dogs 91 from the toothed section 831. Accordingly, the rotational direction of the stem 83 driven by the seat body 82 can be controlled.
The sections of the dogs 91 abutting against the dented sections 822 serve as supporting points for the dogs 91. The free ends of the dogs 91 engaged with the toothed section 831 of the stem 83 are opposite to the sections abutting against the dented sections 822. Accordingly, the arm of resistance of the dogs 91 engaged with the toothed section 831 is considerably long. Therefore, the dogs 91 are easy to deform or break when suffering too great force. Under such circumstance, the ratchet mechanism 9 will fail. Furthermore, the dogs 91 have considerable lengths and swing about the sections abutting against the dented sections 822. Therefore, the drive block 93 needs to push the dogs 91 to swing by a considerable amplitude so as to disengage from the toothed section 831. In the case that the drive block 93 is worn or the dogs 91 are deformed, it often takes place that the dogs 91 cannot be totally disengaged from the toothed section 831 of the stem 93. As a result, the screwdriver can be hardly truly operated.
It is therefore a primary object of the present invention to provide an improved ratchet structure of a screwdriver in which the left and right dogs of the ratchet mechanism are respectively disposed in the left and right splits defined between the stop wall and the post integrally projecting from the seat body. The post is formed with a left and a right projecting sections respectively corresponding to the left and right dogs and inlaid in the left and right notches of the middle sections of the left and right dogs. Accordingly, the post serves to support the left and right dogs, whereby the left and right dogs can swing about the projecting sections inlaid in the left and right notches of the middle sections of the left and right dogs. Therefore, the swinging amplitude of the left and right dogs is reduced and the ratchet screwdriver can be more truly operated.
It is a further object of the present invention to provide the above ratchet structure in which the left and right projecting sections of the post inlaid in the left and right notches of the middle sections of the left and right dogs serve as supports for the left and right dogs. Therefore, the arm of resistance of the left and right dogs engaged with the toothed section of the stem is shortened. Therefore, the left and right dogs can bear greater resistance and the torque value of the ratchet screwdriver is increased.
The present invention can be best understood through the following description and accompanying drawings wherein: